1. Technical Field
The present disclosure relates to a gloss determination device and a gloss determination method for determining a gloss condition of a human face or the like.
2. Description of the Related Art
Gloss sometimes appears on a surface of a substance due to balance between the state of the surface and the illumination condition. Strong gloss on a human face is called “shine”.
In a case, for example, of determining a skin condition such as presence of wrinkles from a photographed image of a human face, the determination accuracy sometimes reduces unless influences of the gloss are considered. On the other hand, it is possible to determine a skin condition such as a sebum level from gloss appearing on the skin. Accordingly, it is beneficial for performing the skin condition determination or the like to determine conditions of gloss such as strength of gloss or distribution of gloss (hereinafter referred to as “gloss conditions”).
Therefore, some techniques for determining the gloss conditions of an object are disclosed in PTL 1 to PTL 3 of the Patent Literatures.
In the technique disclosed in PTL 1, brightness of each pixel is calculated in a photographed image of a substance which is an object to be determined as to its gloss condition (hereinafter referred to as an “object”). In this technique disclosed in PTL 1, a region which has a much higher brightness than major components around the region is determined as a region which has a high gloss level (hereinafter referred to as a “gloss region”).
In the technique disclosed in PTL 2, it is determined that a photographed image of an object contains a gloss region if pixels each having a brightness value equal to or larger than a predetermined threshold value are contained in the image.
In the technique disclosed in PTL 3, a total reflectivity and a quarter value diffuse reflectivity on a surface of an object are measured, where the total reflectivity is a reflectivity of light when natural light enters the surface of the object, and the quarter value diffuse reflectivity is a reflectivity of S polarized component of light when P polarized light enters the surface of the object. Then, in the technique disclosed in PTL 3, strength of gloss is determined based on a value obtained by subtracting a value which is four times as large as the quarter diffuse reflectivity from the total reflectivity.